CN101718570A - Device and method for non-contact detection of water level - Google Patents
Device and method for non-contact detection of water level Download PDFInfo
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- CN101718570A CN101718570A CN200910109878A CN200910109878A CN101718570A CN 101718570 A CN101718570 A CN 101718570A CN 200910109878 A CN200910109878 A CN 200910109878A CN 200910109878 A CN200910109878 A CN 200910109878A CN 101718570 A CN101718570 A CN 101718570A
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Abstract
The invention discloses a device and a method for the non-contact detection of a water level. The device comprises a variable capacitor module, a filtration module, a signal amplification module, a reverse feedback module and a sampling signal generating module, wherein the variable capacitor module generates a capacitor value according to the state of the water level to form harmonic signals; the filtration module is connected with the variable capacitor module to filter low-frequency signals in the harmonic signals; the signal amplification module receives, amplifies and filters the harmonic signals filtered by the filtration module; the reverse feedback module is connected with the signal amplification module for sampling a circuit, acquiring amplitude information and adjusting the working point of the signal amplification module according to the amplitude information; the sampling signal generating module is connected with the signal amplification module to acquire the harmonic signals for coupling, rectifying and filtering so as to form a DC (Direct Current)signal which is sampled by an MCU to acquire a water level state. The method utilizes the variation of the capacitor to embody the variation of the water level so as to generate different harmonic signals which are processed and sampled to acquire the water level state from the sampling values and achieve the aim of detecting the water level.
Description
Technical field
The present invention relates to the water level detecting field, specially refer to a kind of contactless condensate tank of dehumidifier and method.
Background technology
Sensed water level is used level sensor usually in the prior art, and the circuit of level sensor is divided into two kinds of mechanical switch formula and electronic oscillation formulas usually.The wherein simple and realization easily of mechanical switch formula, cost is lower, but gear identification is more coarse; Gear is selected by the user, generally has only high, normal, basic third gear, easily causes the waste to water resource.And electronic oscillation formula cost is higher, but water level identification is very accurate, can realize stepless regulating water level.
Mechanical type level sensor circuit adopts simple shell fragment analog switch, when water level reaches gear, and the shell fragment closure; Just form the requirement of high, normal, basic different shelves water levels again by the stroke that changes the shell fragment closure.The built-in oscillatory circuit of electronic oscillation formula level sensor (lc circuit), the variation of water level causes air pressure change, the variation of air pressure causes that the inductance value (L) of the built-in inductance of level sensor changes, the variation of L causes that oscillation frequency changes, be that interior umber of pulse of unit interval changes, after MCU (Micro Control Unit, micro-control unit) detects frequency signal, obtain corresponding hydraulic pressure amount by lookup table mode, draw corresponding water level amount afterwards.
To the detection of water level, the level sensor of contact need be set separately in the prior art, make whole testing circuit structure comparatively complicated, improve production cost.
Summary of the invention
One of purpose of the present invention has reduced production cost for a kind of contactless condensate tank of dehumidifier and method are provided.
The present invention proposes a kind of contactless condensate tank of dehumidifier, comprising:
Switchable capacitive module produces capacitance according to water position status, forms harmonic signal;
Filtration module is connected with described switchable capacitive module, filters the low frequency signal in the described harmonic signal;
The signal amplification module receives by the harmonic signal after the described filtering module filtration and amplifies and Filtering Processing;
The negative feedback module is connected with described signal amplification module, carries out circuit sampling, obtains amplitude information; And adjust the working point of described signal amplification module according to described amplitude information;
The sampled signal generation module is connected with the signal amplification module, obtains that harmonic signal is coupled, rectification and filtering, forms direct current signal, obtains water position status for the MCU sampling.
Preferably, described switchable capacitive module comprises:
Electric capacity contacts the formation variable capacitance with water, produce different capacitances at different water position status, forms harmonic signal.
Preferably, described filtration module is the RC parallel circuit.
Preferably, described signal amplification module further comprises:
The single step of releasing big unit is connected with described filtration module, and the harmonic signal behind the receiving filtration once amplifies and filtering;
The secondary amplifying unit is connected with described single step of releasing big unit, receives by once amplifying the also harmonic signal of filtering, carries out secondary and amplifies and filtering.
Preferably, described secondary amplifying unit also is connected with described filtration module, forms the loop between filtration module, single step of releasing big unit and the secondary amplifying unit three, and harmonic signal is amplified repeatedly.
Preferably, described negative feedback module further comprises:
Sample circuit is connected with described signal amplification module, obtains range signal;
Feedback circuit is connected with sample circuit, receives range signal and feed back to the signal amplification module to carry out the working point adjustment.
Preferably, described sampled signal generation module further comprises:
Coupling unit is connected with described signal amplification module, and processing is coupled;
Rectification unit is connected with described coupling unit, carries out rectification and handles;
Filter unit is connected with described rectification unit, filters high-frequency signal, forms direct current signal, obtains water position status for the MCU sampling.
The present invention also proposes a kind of contactless level testing methods, comprises step:
Produce capacitance according to water position status, form harmonic signal;
Filter the low frequency signal in the described harmonic signal;
Harmonic signal behind the receiving filtration amplifies and Filtering Processing;
Obtain amplitude information, and carry out the signal amplitude adjustment according to described amplitude information;
Obtain that harmonic signal is coupled, rectification and filtering, form direct current signal, obtain water position status for the MCU sampling.
Preferably, described according to water position status generation capacitance, the step that forms harmonic signal comprises step:
Form variable capacitance by contacting, produce different capacitances, form harmonic signal at different water position status with water.
Preferably, the harmonic signal behind the described receiving filtration amplifies and the step of Filtering Processing further comprises step:
Harmonic signal behind the receiving filtration once amplifies and filtering;
Receive by once amplifying the also harmonic signal of filtering, carry out secondary and amplify and filtering.
Contactless condensate tank of dehumidifier of the present invention and method are utilized capacitance variations to embody SEA LEVEL VARIATION, thereby are produced different harmonic signals, are sampling after treatment, obtain water position status from sampled value, can reach the purpose of sensed water level.
Description of drawings
Fig. 1 is the structural representation of the contactless condensate tank of dehumidifier of one embodiment of the invention;
Fig. 2 is the electrical block diagram of the contactless condensate tank of dehumidifier of one embodiment of the invention;
Fig. 3 is the structural representation of the contactless condensate tank of dehumidifier signal amplification module of one embodiment of the invention;
Fig. 4 is the structural representation of the contactless condensate tank of dehumidifier negative feedback module of one embodiment of the invention;
Fig. 5 is the structural representation of the contactless condensate tank of dehumidifier sampled signal generation module of one embodiment of the invention;
Fig. 6 is the steps flow chart synoptic diagram of the contactless level testing methods of another embodiment of the present invention;
Fig. 7 is the schematic flow sheet of step S22 of the contactless level testing methods of another embodiment of the present invention.
The realization of the object of the invention, functional characteristics and advantage will be in conjunction with the embodiments, are described further with reference to accompanying drawing.
Embodiment
The present invention contacts with tested water by capacitor C 1 (scheming not shown) is set in testing circuit, and this tested water is equivalent to one one end ground connection, the capacitor C 2 that the other end is connected with this capacitor C 1 (scheming not shown).Capacitor C 1 is equivalent to a variable capacitor C x (with reference to Fig. 2) with effect after capacitor C 2 is connected.When the water position status variation of tested water, then the value of this capacitor C 2 will change; Detect the harmonic signal that produces, handle the back and produce direct current signal, for MCU (Micro Control Unit, micro-control unit) carries out AD (Analog Digital, analog/digital) sampling, obtain water position status information, judge water position status, reach the purpose of sensed water level state.
With reference to Fig. 1, a kind of contactless condensate tank of dehumidifier 10 of one embodiment of the invention is proposed, can comprise:
Switchable capacitive module 11 produces capacitance according to water position status, forms harmonic signal;
Sampled signal generation module 15 is connected with signal amplification module 13, obtains that harmonic signal is coupled, rectification and filtering, forms direct current signal, obtains water position status for the MCU sampling.
With reference to Fig. 2, in an embodiment of present embodiment, above-mentioned switchable capacitive module 11 can comprise capacitor C 1, contacts with water to form variable capacitance C2, produces different capacitances at different water position status, forms harmonic signal.Capacitor C 1 contacts with tested water, this tested water is equivalent to the capacitor C 2 that one one end ground connection, the other end are connected with this capacitor C 1, water position status variation when tested water, then the value of this capacitor C 2 will change, make the total capacitance (Cx) of series connection change, and formed the harmonic signal of respective change.
Above-mentioned filtration module 12 can be the RC parallel circuit; Constitute by resistance R 12 and capacitor C 7, receive above-mentioned harmonic signal and attenuate wherein low frequency signal.
With reference to Fig. 3, in another embodiment of present embodiment, above-mentioned signal amplification module 13 can further comprise single step of releasing big unit 131 and secondary amplifying unit 132; This single step of releasing big unit 131 is connected with above-mentioned filtration module 12, and the harmonic signal behind the receiving filtration once amplifies and filtering; This secondary amplifying unit 132 is connected with above-mentioned single step of releasing big unit 131, receives by once amplifying the also harmonic signal of filtering, carries out secondary and amplifies and filtering.
Above-mentioned single step of releasing big unit 131 can be triode Q4, and it can be by the signal after the base stage receiving attenuation, is sent to secondary amplifying unit 132 after amplification and the filtration.
Above-mentioned secondary amplifying unit 132 can be triode Q3, receives the signal that above-mentioned triode Q4 transmits, and amplifies once more and filters the back and export.
Above-mentioned secondary amplifying unit 132 (Q3) also is connected with above-mentioned filtration module 12, form the loop between filtration module 12, single step of releasing big unit 131 (Q4) and secondary amplifying unit 132 (Q3) three, the harmonic signal that filters out behind the low frequency signal is amplified repeatedly.
With reference to Fig. 4, in another embodiment of present embodiment, above-mentioned negative feedback module 14 further comprises sample circuit 141 and feedback circuit 142; This sample circuit 141 is connected with above-mentioned signal amplification module 13, obtains range signal; This feedback circuit 142 is connected with sample circuit, receives range signal and feed back to signal amplification module 13 to carry out the working point adjustment, carries out amplitude limit.
Above-mentioned sample circuit 141 can comprise resistance R 13 and resistance R 14, when signal amplitude is amplified to certain value (assurance deliver to MCU voltage be no more than VCC) by triode Q3, the sample circuit of forming by resistance R 13 and resistance R 14 141, take out the signal amplitude information in the signal that this triode Q3 sends, feed back to the emitter of triode Q4 through capacitor C 8, and then adjust the working point of this triode Q4, the signal limitations that makes triode Q3 output is at certain value.
With reference to Fig. 5, in another embodiment of present embodiment, above-mentioned sampled signal generation module 15 can further comprise coupling unit 151, rectification unit 152 and filter unit 153; This coupling unit 151 is connected with above-mentioned signal amplification module 13, and processing is coupled; This rectification unit 152 is connected with above-mentioned coupling unit 151, carries out rectification and handles; This filter unit 153 is connected with above-mentioned rectification unit 152, filters high-frequency signal, forms direct current signal, obtains water position status for the MCU sampling.
Above-mentioned coupling unit 151 can be capacitor C 9, and it can receive from the signal of the emitter output of triode Q3, is coupled and handles back output.
Above-mentioned rectification unit 152 can comprise diode D5 and diode D6, and both compose in parallel, and the signal through overcoupling is carried out also exporting after rectification is handled.
Above-mentioned filter unit 153 can comprise resistance R 15 and capacitor C 10, and both constitute the RC parallel circuit, and the signal after the reception rectification carries out Filtering Processing, attenuates high-frequency signal, produces direct current signal, carries out the AD sampling for MCU.
MCU samples by AD, can obtain AD value (analog voltage).When water position status (highly) changes, capacitor C 1 will change with the total capacitance (Cx) of capacitor C 2, and the AD value that MCU obtains also can be along with variation, thereby can distinguish different water levels by the variation of AD value, realizes the detection of contactless water level then.
Above-mentioned contactless condensate tank of dehumidifier 10 also can comprise resistance R 10 and resistance R 11, connects with above-mentioned triode Q3 and triode Q4 respectively, can be used for regulating the working point of triode Q3 and triode Q4 respectively.(with reference to Fig. 2)
Above-mentioned contactless condensate tank of dehumidifier 10 also can comprise power supply VCC, and its two ends are connected with the collector of resistance R 10 and triode Q3 respectively.Above-mentioned contactless condensate tank of dehumidifier 10 also is provided with ground connection connection between resistance R 11 and resistance R 14.
Circuit can be arranged on pcb board (Printed CircuitBoard, printed circuit board (PCB)) in the contactless condensate tank of dehumidifier 10 of the present invention; Wherein, above-mentioned capacitor C 1 can be two Copper Foils, and the top layer and the bottom of two-layer printed circuit board is set respectively, and parallel formation one plane-parallel capacitor of two Copper Foils.This contactless condensate tank of dehumidifier 10 is commonly used in the water-level alarm processing, such as in the liquid heating apparatus such as coffee machine and electric kettle, when water level is lower than certain value, just can start warning.This contactless condensate tank of dehumidifier 10, simple in structure, reduced production cost.
With reference to Fig. 6, a kind of contactless level testing methods of another embodiment of the present invention is proposed, can comprise:
Step S20, produce capacitance, form harmonic signal according to water position status;
Low frequency signal in step S21, the described harmonic signal of filtration;
Harmonic signal behind step S22, the receiving filtration amplifies and Filtering Processing;
Step S23, obtain amplitude information, and carry out the signal amplitude adjustment according to described amplitude information;
Step S24, obtain that harmonic signal is coupled, rectification and filtering, form direct current signal, obtain water position status for the MCU sampling.
As described in step S20, by capacitor C 1 being set and contacting with tested water, this tested water is equivalent to the capacitor C 2 that one one end ground connection, the other end are connected with this capacitor C 1, water position status variation when tested water, then the value of this capacitor C 2 will change, make the total capacitance (Cx) of series connection change, and formed the harmonic signal of respective change.
As described in step S21, can utilize the RC parallel circuit to receive above-mentioned harmonic signal and filtration low frequency signal wherein.
With reference to Fig. 7, in an embodiment of present embodiment, above-mentioned steps S22 can further comprise:
Harmonic signal behind step S221, the receiving filtration once amplifies and filtering;
Step S222, reception are carried out secondary and are amplified also filtering by once amplifying the also harmonic signal of filtering.
After carrying out once amplification and secondary amplification, also can return step S21, once more signal is carried out Filtering Processing, and then carry out above-mentioned steps S221 and step S222, signal is amplified repeatedly.
As described in step S23, when signal amplitude is amplified to certain value (assurance deliver to MCU voltage be no more than VCC),, takes out the signal amplitude information in the amplifying signal, and carry out the amplitude limit adjustment by sampling, make signal limitations within certain value.
As described in step S24, obtain through the signal after amplification be coupled, rectification and filtering, form direct current signal, obtain water position status for the MCU sampling.
MCU samples by AD, can obtain the AD value.When water position status (highly) changes, capacitor C 1 will change with the total capacitance (Cx) of capacitor C 2, and the AD value that MCU obtains also can be along with variation, thereby can distinguish different water levels by the variation of AD value, realizes the detection of contactless water level then.
The above only is the preferred embodiments of the present invention; be not so limit claim of the present invention; every equivalent structure or equivalent flow process conversion that utilizes instructions of the present invention and accompanying drawing content to be done; or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present invention.
Claims (10)
1. a contactless condensate tank of dehumidifier is characterized in that, comprising:
Switchable capacitive module produces capacitance according to water position status, forms harmonic signal;
Filtration module is connected with described switchable capacitive module, filters the low frequency signal in the described harmonic signal;
The signal amplification module receives by the harmonic signal after the described filtering module filtration and amplifies and Filtering Processing;
The negative feedback module is connected with described signal amplification module, carries out circuit sampling, obtains amplitude information; And adjust the working point of described signal amplification module according to described amplitude information;
The sampled signal generation module is connected with the signal amplification module, obtains that harmonic signal is coupled, rectification and filtering, forms direct current signal, obtains water position status for the MCU sampling.
2. contactless condensate tank of dehumidifier according to claim 1 is characterized in that, described switchable capacitive module comprises:
Electric capacity contacts the formation variable capacitance with water, produce different capacitances at different water position status, forms harmonic signal.
3. contactless condensate tank of dehumidifier according to claim 1 is characterized in that, described filtration module is the RC parallel circuit.
4. according to any described contactless condensate tank of dehumidifier in the claim 1 to 3, it is characterized in that described signal amplification module further comprises:
The single step of releasing big unit is connected with described filtration module, and the harmonic signal behind the receiving filtration once amplifies and filtering;
The secondary amplifying unit is connected with described single step of releasing big unit, receives by once amplifying the also harmonic signal of filtering, carries out secondary and amplifies and filtering.
5. contactless condensate tank of dehumidifier according to claim 4, it is characterized in that, described secondary amplifying unit also is connected with described filtration module, forms the loop between filtration module, single step of releasing big unit and the secondary amplifying unit three, and harmonic signal is amplified repeatedly.
6. according to any described contactless condensate tank of dehumidifier in the claim 1 to 3, it is characterized in that described negative feedback module further comprises:
Sample circuit is connected with described signal amplification module, obtains range signal;
Feedback circuit is connected with sample circuit, receives range signal and feed back to the signal amplification module to carry out the working point adjustment.
7. according to any described contactless condensate tank of dehumidifier in the claim 1 to 3, it is characterized in that described sampled signal generation module further comprises:
Coupling unit is connected with described signal amplification module, and processing is coupled;
Rectification unit is connected with described coupling unit, carries out rectification and handles;
Filter unit is connected with described rectification unit, filters high-frequency signal, forms direct current signal, obtains water position status for the MCU sampling.
8. a contactless level testing methods is characterized in that, comprises step:
Produce capacitance according to water position status, form harmonic signal;
Filter the low frequency signal in the described harmonic signal;
Harmonic signal behind the receiving filtration amplifies and Filtering Processing;
Obtain amplitude information, and carry out the signal amplitude adjustment according to described amplitude information;
Obtain that harmonic signal is coupled, rectification and filtering, form direct current signal, obtain water position status for the MCU sampling.
9. contactless level testing methods according to claim 8 is characterized in that, described according to water position status generation capacitance, the step that forms harmonic signal comprises step:
Form variable capacitance by contacting, produce different capacitances, form harmonic signal at different water position status with water.
10. according to Claim 8 or 9 described contactless level testing methods, it is characterized in that the harmonic signal behind the described receiving filtration amplifies and the step of Filtering Processing further comprises step:
Harmonic signal behind the receiving filtration once amplifies and filtering;
Receive by once amplifying the also harmonic signal of filtering, carry out secondary and amplify and filtering.
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| CN200910109878A CN101718570A (en) | 2009-11-25 | 2009-11-25 | Device and method for non-contact detection of water level |
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| CN200910109878A CN101718570A (en) | 2009-11-25 | 2009-11-25 | Device and method for non-contact detection of water level |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102429813A (en) * | 2011-09-07 | 2012-05-02 | 上海荣泰健身科技发展有限公司 | Anti-dry-combustion water injection foot massager |
| CN103674177A (en) * | 2013-12-19 | 2014-03-26 | 重庆川仪自动化股份有限公司 | Signal processing method and device |
| CN105300477A (en) * | 2015-11-03 | 2016-02-03 | 天津市飞跃兄弟测控技术有限公司 | Water level measuring method and ruler |
| CN109916961A (en) * | 2019-04-10 | 2019-06-21 | 浙江数链科技有限公司 | A kind of receptacle detection system and surplus test method and device |
-
2009
- 2009-11-25 CN CN200910109878A patent/CN101718570A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102429813A (en) * | 2011-09-07 | 2012-05-02 | 上海荣泰健身科技发展有限公司 | Anti-dry-combustion water injection foot massager |
| CN103674177A (en) * | 2013-12-19 | 2014-03-26 | 重庆川仪自动化股份有限公司 | Signal processing method and device |
| CN103674177B (en) * | 2013-12-19 | 2016-08-17 | 重庆川仪自动化股份有限公司 | A kind of signal processing method and device |
| CN105300477A (en) * | 2015-11-03 | 2016-02-03 | 天津市飞跃兄弟测控技术有限公司 | Water level measuring method and ruler |
| CN105300477B (en) * | 2015-11-03 | 2019-06-25 | 天津市飞跃兄弟测控技术有限公司 | A kind of water level measurement method and water level measuring scale |
| CN109916961A (en) * | 2019-04-10 | 2019-06-21 | 浙江数链科技有限公司 | A kind of receptacle detection system and surplus test method and device |
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Application publication date: 20100602 |